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Wildfires have long been regarded as one chief culprit in regional air pollution, and pose great impacts on climate change. Although climate forcing of wildfire smoke has been widely investigated, its influence on synoptic systems remains unclear. Based on measurement and modeling analysis, the impact of wildfire smoke on the development of a mid‐latitude cyclone was revealed for Canadian wildfires in early June of 2023. The radiative forcing induced by smoke at surface and in the atmosphere reached up to −150 and 100 W m−2, posing opposite tendencies of atmospheric stratification over the land and ocean. Such perturbations contributed to the enhancement and stagnation of the cyclone, which favored the transport of smoke from the fire‐intensive region, indicated by nearly 40% increment of PM2.5 mass flux. With escalating wildfire risk in the future, the inclusion of smoke aerosols' impacts on meteorology in weather forecast models is of great importance. Plain Language Summary: Wildfires are uncontrolled fires that burn in the wildland vegetation, posing great challenges to regional air quality and global climate. Wildfire smoke has been known to exert great climate forcing via aerosol‐radiation interaction yet its impact on synoptic scales needs further investigation. Here, based on comprehensive observations and modeling analysis for the extreme Canadian wildfires in early June of 2023, smoke aerosol is revealed to induce significant radiative forcing and yield opposite modifications of temperature stratification over the land and ocean, resulting in intensified and stagnant mid‐latitude cyclone. Such perturbations favored the transport of smoke from fire‐intensive region to downwind cities in Canada and United States, and the subsequent long‐range transport dominated by the cyclone. Key Points: Smoke from intensive Canadian wildfires in early June of 2023 degraded the air quality of cities in eastern Canada and United StatesThe wildfire smoke enhanced the development of the mid‐latitude cyclone via smoke aerosol‐radiation interactionThe intensification and stagnation of the cyclone facilitated the transport of smoke to downwind cities in northeastern United States [ABSTRACT FROM AUTHOR]